Exchange server 2013 with two Mailbox server role and One CAS server role with DAG Enabled on it.
Exchange server went live with 150 Mailbox on both the server distributed evenly.
Both mailbox server lost connectivity and unable to communicate with CAS server.
Outlook and OWA user unable to connected to their mailboxes.
Both the Mailbox server went down disrupting the mailflow.
Later found that Cluster Node wasnt responding in timely fashion. Had to remove the Mailboxes from the DAG and later remove the DAG configuration.
Disable Replication network on each of the mailbox server and rebooted it.
Re gain network connectivity to the Mailboxes and they are back on online.
What could be the issue.
Both mailbox server are rich in resources which can be ruled here